Scheduling model of parallel batch process based on pre-ordering

For a parallel batch process, a scheduling model based on due dates was built to minimize the total earliness. Considering the due dates of orders and other constraint conditions, the assignment of orders and units is described by a set of binary variables. The processing sequence of orders is determined by the pre-ordering method. The model is solved by Branch and Bound approach. The computational study shows that the proposed model achieves significant improvement over the model in the literatures.